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44
result(s) for
"Vannan, Mani A"
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A Mouse Model of Mitochondrial Disease Reveals Germline Selection against Severe mtDNA Mutations
by
Coskun, Pinar E.
,
Fan, Weiwei
,
MacGregor, Grant R.
in
animal models
,
Animals
,
Biological and medical sciences
2008
The majority of mitochondrial DNA (mtDNA) mutations that cause human disease are mild to moderately deleterious, yet many random mtDNA mutations would be expected to be severe. To determine the fate of the more severe mtDNA mutations, we introduced mtDNAs containing two mutations that affect oxidative phosphorylation into the female mouse germ line. The severe ND6 mutation was selectively eliminated during oogenesis within four generations, whereas the milder COI mutation was retained throughout multiple generations even though the offspring consistently developed mitochondrial myopathy and cardiomyopathy. Thus, severe mtDNA mutations appear to be selectively eliminated from the female germ line, thereby minimizing their impact on population fitness.
Journal Article
A proposal of a simplified grading and echo-based staging of aortic valve stenosis to streamline management
2024
In this paper we discuss the relevance of continuity equation based aortic valve area (AVA) calculation as a robust parameter suitable for accurate grading of aortic stenosis (AS) irrespective of flow conditions. Combining the AVA-based
grading
and echocardiography-based
staging
, can provide with the most comprehensive clinical assessment of patients with AS and preserved left ventricular systolic function to streamline management decisions.
Journal Article
The added value of three-dimensional transthoracic echocardiography in mitral annular disjunction: a case report
by
Papadopoulos, Konstantinos
,
Vannan, Mani A.
,
Ikonomidis, Ignatios
in
3D echocardiography
,
4D strain
,
arrhythmic mitral valve prolapse
2024
Mitral annular disjunction (MAD) refers to the arrhythmic mitral valve prolapse (MVP) syndrome associated with ventricular arrhythmias and sudden cardiac death. Although the pathophysiology of this disease is still under investigation, specific imaging criteria that establish the diagnosis have been recognized. In this article, we demonstrate most of these criteria using three-dimensional transthoracic echocardiography (3D-TTE) and provide added value in the management of MAD syndrome.
A 50-year-old male patient with recent syncope and a history of mitral regurgitation (MR) and MAD was admitted to our clinic for further investigation. According to our protocol, the patient underwent a complete 3D-TTE, laboratory blood exams, and 24 h ambulatory electrocardiogram (ECG). Our investigation confirmed the presence of MAD syndrome with bileaflet prolapse, severe MR, and non-sustained ventricular tachycardia, necessitating an implantable cardioverter defibrillator (ICD) and surgical mitral valve repair. The 3D-TTE analysis of the mitral valve demonstrated mitral annular systolic expansion and systolic flattening of the saddle-shaped annulus and quantified the extent of the disjunction arc. Additionally, four-dimensional (4D) strain analysis of the left ventricle revealed the presence of fibrosis of the posteromedial papillary muscle and basal inferolateral wall, which are variables that are required for the diagnosis and therapeutic management of MAD syndrome.
3D-TTE and 4D strain offer valuable insights for diagnosing and managing patients with MAD syndrome. This method seems to correlate well with the other imaging modalities and could be included in the management protocol of MAD syndrome.
Journal Article
Timing of Intervention in Aortic Stenosis
2020
Current guidelines require that in patients with severe aortic stenosis, symptoms related to the valvular disease be present for consideration of transcatheter aortic-valve replacement (TAVR) or surgical aortic-valve replacement.
1,2
In the absence of symptoms, only very severe aortic stenosis is an indication (class IIa) for intervention.
1-3
Kang et al.
3
now report in the
Journal
the results of a trial involving patients with asymptomatic, very severe aortic stenosis who were randomly assigned to surgical aortic-valve replacement or conservative care (clinical follow-up and observation). Outcomes (death during or within 30 days after surgery [operative mortality] or death from cardiovascular causes; death from . . .
Journal Article
Effects of MitraClip Therapy on Mitral Flow Patterns and Vortex Formation: An In Vitro Study
by
Hatoum Hoda
,
Gooden, Shelley Chee-Mei
,
Boudoulas Konstantinos Dean
in
Acceleration
,
Biomedical engineering
,
Bladder
2022
MitraClip transcatheter edge-to-edge repair is used to treat mitral regurgitation (MR). While MR is reduced, diastolic left ventricular flows are altered. An in vitro left heart simulator was used to assess a porcine mitral valve in the native, MR, and MR plus MitraClip cases. Velocity, vorticity, and Reynolds shear stress (RSS) were quantified by particle image velocimetry. Peak velocity increased from 1.20 m/s for native to 1.30 m/s with MR. With MitraClip, two divergent jets of 1.18 and 0.61 m/s emerged. Higher vorticity was observed with MR than native and lessened with MitraClip. MitraClip resulted in shear layer formation and downstream vortex formation. Native RSS decreased from 33 Pa in acceleration to 29 Pa at peak flow, then increased to 31 Pa with deceleration. MR RSS increased from 27 Pa in acceleration to 40 Pa at peak flow to 59 Pa during deceleration. MitraClip RSS increased from 79 Pa in acceleration to 162 Pa during peak flow, then decreased to 45 Pa during deceleration. After MitraClip, two divergent jets of reduced velocity emerged, accompanied by shear layers and recirculation. Chaotic flow developed, resulting in elevated RSS magnitude and coverage. Findings help understand consequences of MitraClip on left ventricular flow dynamics.
Journal Article
Mortality Associated With Proportionality of Secondary Mitral Regurgitation After Transcatheter Mitral Valve Repair: North American Mitraclip for Functional Mitral Regurgitation Registry
by
Engoren, Milo
,
Duggal, Neal M.
,
Chadderdon, Scott M.
in
Cardiomyopathy
,
Confidence intervals
,
Death & dying
2024
The association, if any, between the effective regurgitant orifice area (EROA) to left ventricular end-diastolic volume (LVEDV) ratio and 1-year mortality is controversial in patients who undergo mitral transcatheter edge-to-edge repair (m-TEER) with the MitraClip system (Abbott Vascular, Santa Clara, CA). This study's objective was to determine the association between EROA/LVEDV and 1-year mortality in patients who undergo m-TEER with MitraClip. In patients with severe secondary (functional) mitral regurgitation (MR), we analyzed registry data from 11 centers using generalized linear models with the generalized estimating equations approach. We studied 525 patients with secondary MR who underwent m-TEER. Most patients were male (63%) and were New York Heart Association class III (61%) or IV (21%). Mitral regurgitation was caused by ischemic cardiomyopathy in 51% of patients. EROA/LVEDV values varied widely, with median = 0.19 mm2/ml, interquartile range [0.12,0.28] mm2/ml, and 187 patients (36%) had values <0.15 mm2/ml. Postprocedural mitral regurgitation severity was substantially alleviated, being 1+ or less in 74%, 2+ in 20%, 3+ in 4%, and 4+ in 2%; 1-year mortality was 22%. After adjustment for confounders, the logarithmic transformation (Ln) of EROA/LVEDV was associated with 1-year mortality (odds ratio 0.600, 95% confidence interval 0.386 to 0.933, p = 0.023). A higher Society of Thoracic Surgeons risk score was also associated with increased mortality. In conclusion, lower values of Ln(EROA/LVEDV) were associated with increased 1-year mortality in this multicenter registry. The slope of the association is steep at low values but gradually flattens as Ln(EROA/LVEDV) increases.
Journal Article
Initial Experience with the 4D Mini-TEE Probe in the Adult Population
by
Donal, Erwan
,
Papadopoulos, Konstantinos
,
Antoniadis, Antonios P.
in
Accuracy
,
Bioengineering
,
Esophagus
2024
Background: Transesophageal echocardiography (TEE) is a vital diagnostic tool in clinical practice, particularly in transcatheter interventions where it aids in both pre-operative planning and intra-operative guidance. Traditional TEE probes often require general anesthesia due to patient discomfort. However, the development of miniaturized TEE probes presents a promising alternative, enabling routine examinations and interventions with minimal sedation. This study evaluates the feasibility of performing a complete 2D/4D TEE protocol with the new 4D mini-TEE probe in the echocardiography department and its application in transcatheter interventions. Methods: This is a retrospective study that included 30 consecutive patients from two high-volume European hospitals (Interbalkan Medical Center, Thessaloniki, Greece, and Rennes University, France) that underwent TEE or transcatheter interventions. The new 4D mini-TEE 9VT-D probe (GE Healthcare) was utilized. The quality of the images and the tolerance of the probe were assessed in the cath lab during interventions and in the echocardiography department during routine TEE examinations. Results: Direct comparison of the 4D mini-TEE probe with the standard 6VT-D probe confirmed the excellent image quality of this new pediatric probe. Most of the patients required minimal sedation or local oropharyngeal anesthesia, with satisfactory tolerance reported. Most of the transcatheter procedures did not require general anesthesia and intubation, resulting in shorter procedural time. Both 2D and 4D imaging modalities offered adequate intra-operative guidance for transcatheter procedures. Conclusions: The 4D mini-TEE probe delivers exceptional imaging capabilities for routine examinations and transcatheter interventions without needing sedation. Its use reduces esophageal trauma and the need for general anesthesia, enhancing patient comfort and safety.
Journal Article
Intraoperative embolism of a right atrial myxoma: a case report
by
Alexiou, Christos
,
Ozden Tok, Ozge
,
Papadopoulos, Konstantinos
in
Case Reports
,
Embolization
,
Pulmonary arteries
2020
Abstract
Background
Atrial myxomas are the most common benign cardiac tumours. Clinical manifestations vary from constitutional symptoms, to valvular stenosis and embolic events, and surgical removal is the only suggested treatment.
Case summary
A 50-year-old female patient was referred to our centre for surgical excision of a reported right atrial mass. A transoesophageal echocardiographic exam revealed two right atrial masses and the surgical plan was total removal of both masses. However, during the operation the surgeons were not able to locate the larger of the two masses and embolization to the pulmonary trunk was considered as the most likely explanation in this setting. A control suction of the right ventricle and the proximal part of the pulmonary arteries was performed to check if the mass had embolized distally but this did not yield any mass. The patient was transferred to the intensive care unit and remained stable for 2 h, until she developed an abrupt cardiogenic shock with signs of right heart failure. An emergent pulmonary computed tomography angiography demonstrated the embolized mass to the left pulmonary artery and the patient was retransferred to the operating room for emergent surgical removal of the mass. The patient showed immediate clinical and haemodynamic improvement after the removal of this mass and had an uneventful further hospitalization.
Discussion
Multiple right atrial myxomas are rarely reported and surgical excision requires experience, as in case of embolization immediate removal must be obtained to prevent from right ventricle distress and cardiogenic shock.
Journal Article
Transcription profile of DNA damage response genes at G0 lymphocytes exposed to gamma radiation
2012
Ionizing radiation induces a plethora of DNA damages in human cells which may alter the level of mRNA expression. We have analyzed mRNA expression profile of DNA damage response genes involved in G
0
/G
1
check point pathway in whole blood to assess their radio-adaptive response, if any, to gamma radiation. Blood samples were collected from twenty-five random, normal, and healthy male donors with written informed consent and irradiated at doses between 0.1 and 2.0 Gy (0.7 Gy/min). DNA strand breaks were studied using comet assay, whereas DNA double-strand breaks were visualized using γH2AX as a biomarker. Dose response if any, at transcriptional level was studied for all these dose groups at 1 and 5-h post-irradiation. Adaptive response at transcriptional level was studied at three different priming doses (0.1, 0.3, and 0.6 Gy) separately followed by a challenging dose of 2.0 Gy after 4 h. For both the experiments, total RNA was isolated from PBMCs obtained from irradiated whole blood and reverse transcribed to cDNA. The level of mRNA expression of ATM, ATR, GADD45A, CDKN1A, P53, CDK2, MDM2, and Cyclin E was studied using real-time quantitative PCR. A significant dose-dependant increase in the percentage of DNA damage in tail was observed using comet assay. Similarly, increased number of foci was observed at γH2AX with increasing dose. At transcriptional level, a significant dose-dependent up-regulation at GADD45A, CDKN1A, and P53 genes up to 1.0 Gy was observed at 5-h post-irradiation (
P
≤ 0.05). Radio-adaptive response at mRNA expression level was observed at CDK2, Cyclin E, and P53, whereas ATM, ATR, GADD45A, MDM2, ATM, and ATR have not shown any radio-adaptive changes in the expression profile. DNA damage response genes involved in G
0
/G
1
checkpoint pathway has important implications in terms of radiosensitivity in vivo and changes in the transcriptional profile might throw some new insights to understand the mechanism of adaptive response.
Journal Article